JPH0525251A - Sealing epoxy resin composition - Google Patents

Abstract

PURPOSE:To obtain the subject composition resistant to cracking and excellent in humidity and heat resistances by mixing a specified biphenyl epoxy resin with a specified dicyclopentadiene phenol polymer and a specified naphthol phenol polymer as essential components. CONSTITUTION:This composition essentially consists of a biphenyl epoxy resin of formula I (wherein (a) is a number of 0-1.0 and represents the number of repeating units), a dicyclopentadiene phenol polymer of formula II (wherein R is H or CnH2n+1, (n) is an integer of 1 or greater, and (b) is 0 or greater) and a naphthol phenol polymer of formula III (wherein R is CnH2n+1, (n) is an integer of 0 or greater, and (c) is 1 or greater).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealing epoxy resin composition which is resistant to cracking and has excellent moisture resistance and heat resistance.

[0002]

2. Description of the Related Art A method for sealing electronic parts such as semiconductors with a thermosetting resin composition is generally used. In this case, an epoxy resin composition is most commonly used as the thermosetting resin composition. This epoxy resin composition includes, for example, cresol novolac type epoxy resin, bisphenol A type epoxy resin, aliphatic cyclic epoxy resin and other epoxy resins; phenol novolac and other curing agents; tertiary amine and imidazole and other curing accelerators; silica. Filler made of inorganic fine powder such as alumina and alumina; Coupling agent such as silane coupling agent;
A release agent such as carnauba wax or stearic acid; a coloring agent such as carbon black.

Recently, in order to reduce the size and thickness of electronic parts, the semiconductor mounting method is the conventional pin insertion method (DI).
P: dual in-line package, etc.) to a surface mounting method (SOP: small outline package, QFP: quad flat package, etc.). In the case of the surface mounting method, the semiconductor package is processed at a high temperature (for example, 210 to 270 ° C.) such as being immersed in a solder bath during mounting, and at that time, high temperature heat is applied to the entire package. A package sealed with the above-mentioned conventional sealing resin composition causes problems such as cracking in the sealing resin portion or a significant decrease in moisture resistance in this process, May not be used as

The occurrence of cracks in the soldering process is
It is said that moisture absorbed between the post-curing and the mounting process explosively turns into steam and expands during heating by soldering. Therefore, as a countermeasure, a method of completely drying the post-cured package, storing it in a sealed container, and shipping it is used.

Further, various improvements of the encapsulating resin composition itself have been studied. For example, JP-A-64-87616 and JP-A-1-108256 propose a sealing resin composition in which a biphenyl type epoxy resin is used as an epoxy resin and a general curing agent is used as a curing agent. Has been done. Further, in JP-A-62-184020, JP-A-62-104830, and the like, a dicyclopentadiene / phenol polymer is used as a curing agent, and a general epoxy resin is used as an epoxy resin. Compositions have been proposed. However, the encapsulating resin compositions proposed in these publications have not yet been sufficiently effective and there is room for improvement.

[0006]

The above-mentioned method of enclosing the dry package in the container has a drawback that the manufacturing process and the work of handling the product are complicated. Therefore, currently
It is strongly desired to develop a resin composition for encapsulation corresponding to the progress of surface mounting technology. In view of such a situation, the present invention is a resin encapsulation that is less likely to crack when exposed to high temperatures in the above-mentioned soldering process, has superior moisture resistance reliability, and can sufficiently withstand surface mounting. An object is to provide an epoxy resin composition for encapsulation that enables resin-encapsulated electronic components such as static semiconductor devices.

[0007]

In order to solve the above-mentioned problems, an epoxy resin composition for encapsulation according to the present invention comprises a biphenyl type epoxy resin (A) represented by the following general formula, and a biphenyl type epoxy resin represented by the following general formula. The dicyclopentadiene / phenol polymer (B) and the naphthol / phenol polymer (C) represented by the following general formula are essential components.

[0008]

[Chemical 4]

[0009]

[Chemical 5]

[0010]

[Chemical 6]

The epoxy resin (A), which is one of the essential components of the encapsulating epoxy resin composition of the present invention, has a rigid biphenyl skeleton, and thus has a low elastic modulus and an excellent strength at the time of heating. There is. Further, since it has a hydrophobic methyl group in the phenyl skeleton, it also has a characteristic that the hygroscopicity becomes small. This epoxy resin (A) has a general formula (structural formula)
When the number of repeating units a therein is within the range of 0 to 1.0, effective heat resistance is exhibited. The number of repeating units a is preferably 0. When a becomes large, Tg which is an index of heat resistance
(Glass transition temperature) decreases, and strength at high temperature also decreases.

The above-mentioned dicyclopentadiene / phenol polymer (polymer of dicyclopentadiene and phenol) (B), which is the second essential component, is a curing agent. By using such a curing agent as an essential component, the hygroscopicity of the cured product becomes small and, moreover, it has the same heat resistance as when a general phenol novolac curing agent is used. The number of repeating units b in the general formula may be 0 or more,
From the viewpoint of exhibiting effective heat resistance and / or hygroscopicity, 15 or less is preferable, and 5 or less is more preferable.

The above-mentioned naphthol-phenol polymer (polymer of naphthol and phenol) which is the third essential component
(C) is also a curing agent. By using such a curing agent together, the hygroscopicity of the cured product becomes extremely small, and the moisture resistance reliability of the sealing resin can be significantly improved. The number of repeating units c in the general formula may be 1 or more, but is preferably 10 or less and more preferably 5 or less from the viewpoint of exhibiting effective heat resistance and / or hygroscopicity.

The mixing ratio of the above two kinds of phenolic curing agents (B) and (C) is not particularly limited, but for example,
Hydroxyl equivalent ratio: (C) / [(B) + (C)] = 0.1
As described above, 0.9 or less is desirable, and 0.3 or more and 0.7 or less is more desirable. If the equivalent ratio is too small, the moisture resistance reliability tends to deteriorate, and if it is too large, the crack resistance in the soldering process and the like tends to decrease.

The epoxy resin composition for sealing according to the present invention contains the above-mentioned biphenyl type epoxy resin (A), dicyclopentadiene / phenol polymer (B) and naphthol / phenol polymer (C) as essential components. However, even if any of these (A), (B), and (C) is lacking, a significant improvement in crack resistance and moisture resistance reliability during soldering cannot be expected.

In addition to the above essential components, the epoxy resin composition for encapsulation of the present invention may also contain a suitable curing accelerator, inorganic filler, release agent, coloring agent, stress reducing agent, etc., if necessary. Can be added. Examples of the curing accelerator include 1,8-diaza-bicyclo (5,4,0) undecene-7, triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, tris (dimethylaminomethyl) phenol and the like. Tertiary amines; 2-methylimidazole, 2-ethyl-4
-Methylimidazole, 2-phenylimidazole, 2
-Phenyl-4-methylimidazole, 2-heptadecylimidazole and other imidazoles; tributylphosphine, methyldiphenylphosphine, triphenylphosphine, diphenylphosphine, phenylphosphine and other organic phosphines (phosphorus curing accelerators); tetraphenylphosphonium Tetraphenyl borate, triphenylphosphine tetraphenyl borate, 2-ethyl-4
There are tetraphenylboron salts such as -methylimidazole tetraphenylborate and N-methylmorpholine tetraphenylborate. Examples of the inorganic filler include those commonly used for resin encapsulating materials such as silica and alumina. The inorganic filler may be surface-treated with a coupling agent for the purpose of improving adhesion with the sealing resin. Examples of the coupling agent used for the surface treatment of such an inorganic filler include silane coupling agents such as γ-glycidoxypropyltrimethoxysilane and γ-aminopropyltriethoxysilane. Examples of the releasing agent include carnauba wax, stearic acid, montanic acid, and carboxyl group-containing polyolefin, and examples of the coloring agent include carbon black. Examples of the stress reducing agent include silicone gel, rubber and oil. The curing accelerator, inorganic filler, release agent, colorant, stress reducing agent, etc. used in the encapsulating epoxy resin composition of the present invention are not limited to those exemplified here.

In the encapsulating epoxy resin composition of the present invention, other epoxy resins may be used in combination as long as they contain the diphenyl type epoxy resin (A). For example, any number of commonly used epoxy resins such as phenol novolac type epoxy resin and orthocresol novolac type epoxy resin may be used as appropriate as long as the above diphenyl type epoxy resin (A) is used within a range not impairing the effects of the present invention. It can be used together with. As for the curing agent, the above dicyclopentadiene
As long as it contains the phenol polymer (B) and the naphthol-phenol polymer (C) as essential components,
A curing agent other than the above (B) and (C) may be used in combination. Examples of such curing agents other than (B) and (C) include phenol novolac and cresol novolac that are commonly used.

Biphenyl type epoxy resin (A)
And the equivalent ratio of the dicyclopentadiene / phenolic polymer (B) and the naphthol / phenolic polymer (C) are not particularly limited, but may be [the total number of hydroxyl groups of (B) and (C)] / [( A) number of epoxy groups] = 0.7-1.
3 is desirable, and 0.9 to 1.1 is more desirable. In addition,
When other epoxy resins and / or curing agents are used in combination, (total number of hydroxyl groups in all curing agents) / (total number of epoxy groups in all epoxy resins) = 0.7 to 1.3,
0.9 to 1.1 is more desirable.

[0019]

According to the present invention, since the biphenyl type epoxy resin (A), the dicyclopentadiene / phenol polymer (B) and the naphthol / phenol polymer (C) are used together, the reflow resistance (at the time of soldering) It is possible to obtain a sealing resin having good moisture resistance, heat resistance, and mold releasability (molding workability). The reason is presumed as follows. The biphenyl type epoxy resin (A) exhibits the features of low moisture absorption, high heat resistance and low elastic modulus due to the rigid biphenyl skeleton having a hydrophobic methyl group. Since the dicyclopentadiene-phenol polymer (B), which is one of the curing agents used in combination, has a dicyclopentadiene skeleton in its structure, it exhibits a feature of extremely low moisture absorption and is compatible with lead frames and semiconductor devices. The other naphthol-phenol polymer (C) has improved adhesiveness, and since it has a naphthalene skeleton in its structure, it exhibits low moisture absorption and excellent heat resistance (high Tg) and also has improved moisture resistance reliability.

[0020]

EXAMPLES Specific examples and comparative examples of the present invention will be shown below, but the present invention is not limited to the following examples. -Example 1-The raw materials shown in Table 1 were blended in the proportions shown in the same table, and kneaded using a heating roll at a temperature of 70 to 120 ° C for about 8 minutes. Then, it was pulverized to about 5 mmφ to produce the encapsulating epoxy resin composition (epoxy resin molding material) of Example 1.

-Examples 2 to 5 and Comparative Examples 1 to 2 The raw materials shown in Table 1 were used in the proportions shown in the same table, and in the same manner as in Example 1, in Examples 2 to 5 and Comparative Examples 1 and 2. An epoxy resin composition for sealing (epoxy resin molding material) was produced. The biphenyl type epoxy resin (A) shown in Table 1 has the following structural formula;

[0022]

[Chemical 7]

Epoxy equivalent 190, melting point 1
An epoxy resin “YX4000H” (trade name of Yuka Shell Epoxy Co., Ltd.) at 05 ° C. was used. The dicyclopentadiene / phenolic polymer (B) shown in Table 1 has the following structural formula;

[0024]

[Chemical 8]

The phenolic curing agent "DC1" having an average molecular weight of 550, an OH equivalent of 177 and a melting point of 110 ° C.
"00LL" (trade name of Sanyo Kokusaku Pulp Co., Ltd.) was used. The naphthol-phenol polymer (C) shown in Table 1 has the following structural formula;

[0026]

[Chemical 9]

OH equivalent 140, melting point 120
A ° C phenolic curing agent "OCN-7000" (trade name of Nippon Kayaku Co., Ltd.) was used. In this case, as the epoxy resin other than (A), a cresol novolac type epoxy resin “ES having an epoxy equivalent of 195 and a melting point of 70 ° C.“ ES ”is used.
"CN195XL" (trade name of Sumitomo Chemical Co., Ltd.) was used. As the curing agent other than (B) and (C), O is used.
Phenol novolac "Tamanol 752" (trade name of Arakawa Chemical Industry Co., Ltd.) having an H equivalent of 104 and a melting point of 82 ° C was used.

The fused silica fine powder contains 810 parts by weight of the fused silica fine powder in an amount of 2.5 parts by weight of γ-glycidoxypropyltrimethoxysilane and 2.5 parts by weight of γ-aminopropyltriethoxysilane. Then, it was obtained by surface-treating fine powder of fused silica by a spraying method.

[0029]

[Table 1]

The molding materials obtained in the above-mentioned Examples and Comparative Examples were subjected to 170-175 by using a transfer molding machine.
Molded at 90 ° C for 90 seconds and post-cured at 175 ° C for 6 hours to obtain the following moisture absorption rate, solder crack resistance, and moisture resistance reliability evaluation samples. Various characteristics were measured and evaluated by the following methods, and the results are shown in Table 2.

(1) Moisture absorption rate A disk having a diameter of 60 mm and a thickness of 2.0 mm was formed at 85 ° C.
Moisture absorption was performed at 85% RH for 72 hours, and the moisture absorption rate was determined from the weight change. (2) Solder crack resistance 7.6 mm × 7.6 mm × 0.4 mm thick semiconductor element is mounted on a 42 alloy lead frame with a die pad size of 8.2 mm × 8.2 mm using silver paste, and the external dimension is 19 mm.
Molded with a 60-pin flat package type IC mold of × 15 mm × 1.8 mm in thickness, then 85 ° C, 85% R
After absorbing moisture with H for 72 hours, it was immersed in a solder bath at 240 ° C. At this time, the number of samples in which no crack was generated after immersion for 20 seconds (the number of samples without cracks) / (the number of samples immersed in 20 seconds) was examined.

(2) Moisture resistance reliability (USPCBT) The semiconductor element for evaluation (TEG: Test Ele) described in (2) above.
ment group. 0.5 μm comb-shaped aluminum wiring circuit processed, with glass-based protective film) was used to absorb moisture at 85 ° C. and 85% RH for 72 hours.
After immersing in a solder bath at 0 ° C for 10 seconds, 138.5 °
The moisture resistance reliability was measured under the conditions of C, 85% RH and 20V. The percent defective after 300 hours was determined.

[0033]

[Table 2]

As can be seen from Table 2, the examples have a lower moisture absorption rate than the comparative examples, so that the solder crack resistance after moisture absorption is remarkably excellent and the moisture resistance reliability is very high. good.

[0035]

As described above, the epoxy resin composition for encapsulation according to the present invention can significantly reduce the moisture absorption rate of the obtained encapsulating resin and can be mounted on the encapsulating resin. High strength can be maintained even at high temperature, and the moisture resistance reliability of the encapsulating resin can be significantly improved, so that the industrial value is great. Further, the adhesion strength of the obtained sealing resin with a semiconductor device (for example, a semiconductor chip or the like), a lead frame or the like can be improved. Therefore, when the encapsulating epoxy resin composition according to the present invention is used, it is possible to significantly improve the crack resistance in the soldering step during mounting. That is, in the package sealed with the sealing epoxy resin composition of the present invention, firstly, the intrusion of water, which is one of the causes of the package crack or the like that occurs during soldering, is small, and the crack is less likely to occur. On the other hand, since the sealing resin part of the package has a low elastic modulus and high adhesion, interface peeling between the lead frame, semiconductor device, etc. and the sealing resin is suppressed, and the strength at high temperature is high, so that water vapor during mounting Also endures.

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[Procedure amendment]

[Submission date] October 4, 1991

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

[Claims]

[Chemical 1]

[Chemical 2]

[Chemical 3]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction content]

[0009]

[Chemical 5]

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction content]

[0017] In the epoxy resin composition for encapsulating of the present invention, as long includes the biphenyl type epoxy resin (A), the can may be used together other than epoxy resin. For example, commonly used phenol novolak type epoxy resin, an epoxy resin, such as ortho-cresol novolak type epoxy resin, within a range that does not impair the effects of the present invention, as appropriate and in many kinds, the biphenyl type epoxy resin (A ) Can be used together. As for the curing agent, the above dicyclopentadiene
As long as it contains the phenol polymer (B) and the naphthol-phenol polymer (C) as essential components,
A curing agent other than the above (B) and (C) may be used in combination. Examples of such curing agents other than (B) and (C) include phenol novolac and cresol novolac that are commonly used.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0028

[Correction method] Change

[Correction content]

The fused silica fine powder is shown in Table 1.
At a rate of molten silica mosquitoes in against γ- glycidoxypropyltrimethoxysilane 2.5 parts by weight of γ- aminopropyltriethoxysilane 2.5 parts by weight of the parts, by spraying, surface fine powder of fused silica It was obtained by processing.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0033

[Correction method] Change

[Correction content]

[0033]

[Table 2]

Continuation of the front page (51) Int.Cl. ⁵ Identification number In-house reference number FI Technical indication location H01L 23/31 (72) Inventor Tatsuka Wada 1048 Kadoma, Kadoma-shi, Osaka Prefecture Matsushita Electric Works Co., Ltd.

Claims (1)

Claims: 1. A biphenyl type epoxy resin (A) represented by the following general formula, a dicyclopentadiene / phenol polymer (B) represented by the following general formula, and a general formula shown below. An epoxy resin composition for encapsulation containing a naphthol / phenol polymer (C) as an essential component. [Chemical 1] [Chemical 2] [Chemical 3]